Seal plates in gear assemblies or elsewhere in gas turbine engines have numerous functions. First, seal plates act as a seal between a shaft and bearing, for example, in a bull gear. Seal plates can also act to distribute oil thrown outward during rotation of the shaft for both cooling and lubrication. In some cases, a seal plate has an annulus connected to slots to allow oil to pool and be distributed in different proportions to components coupled to the seal plate. Lastly, the seal stands inline in the engine component stack as one of the load bearing elements in the stack.
However, design pressures continue to limit the space available for prior art implementations of seal plates. Many parts simply need to be smaller, which limits the use of prior art oil distribution techniques for many of the following reasons. Smaller components may make the seals more susceptible to uneven thermal expansion when oil cooling passages are widely spaced in some prior embodiments. The need for more even cooling to minimize these expansion effects leads to increased holes and slots in the seal plates for oil flow. This has at least two effects: One, precise manufacturing controls are required for drilling cooling holes through the seal plates into the oil distribution slots of the inner wall of the seal. Two, the increased number of cooling passages and slots reduces the mechanical strength of the seal to bear the loads of the engine component stack.
Further, seals used in different applications may have slightly different requirements for cooling and oil flow distribution. This leads to increased inventory and more customization in the manufacturing processes for different engines.